Photocurable halofluorinated acrylates

ABSTRACT

This invention relates to a novel class of halofluorinated acrylates and more particularly to chlorofluorinated or bromofluorinated acrylates characterized by a chlorofluorinated or bromofluorinated alkylene moiety with acrylate functions at both terminals. These chlorofluorinated acrylates may be photocured in the presence of a photoinitiator into transparent polymers useful as optical waveguiding materials.

BACKGROUND OF THE INVENTION

[0001] This invention relates to a novel class of halofluorinatedacrylates and more particularly to chlorofluorinated or bromofluorinatedacrylates characterized by chlorofluorinated alkylene moiety withacrylate functions at both terminals. These chlorofluorinated orbromofluorinated acrylates may be photocured in the presence of aphotoinitiator into transparent polymers useful as optical waveguidingmaterials.

[0002] The use of photocuring technology has grown rapidly within thelast decade. Photocuring involves the radiation induced polymerizationor crosslinking of monomers into a three dimensional network. Thepolymerization mechanism can be either radical or cationic. Radicalinitiated polymerization is the most common. Most commercial photocuringsystems consist of multifunctional acrylate monomers and free radicalphotoinitiators. Photocuring has a number of advantages including: a100% conversion to a solid composition, short cycle times and limitedspace and capital requirements.

[0003] Photocuring technology has recently been applied in planarwaveguide applications. See, B. M. Monroe and W. K. Smothers, inPolymers for Lightwave and Integrated Optics, Technology andApplications, L. A. Hornak, ed., p. 145, Dekker, 1992. In its simplestapplication, a photocurable composition is applied to a substrate andirradiated with light in a predetermined pattern to produce (the lighttransmissive) or waveguide portion on the substrate. Photocurringpermits one to record fine patterns (<1 um) directly with light. Therefractive index difference between the substrate and the lighttransmissive portion of the substrate can be controlled by eitherregulating the photocurable composition or the developing conditions.

[0004] Because of the dramatic growth in the telecommunications industrythere is a need to develop photocurable compositions for opticalwaveguide and interconnect applications. In order to be useful in theseapplications, the photocurable composition must be highly transparent atthe working wavelength and possess low intrinsic absorption andscattering loss. Unfortunately, in the near-infrared region, among whichthe 1300 and the 1550 nm wavelengths are preferred for opticalcommunications, conventional photocurable materials possess neither therequired transparency or low intrinsic absorption loss.

[0005] The absorption loss in the near-infrared stems from the highharmonics of bond vibrations of the C—H bonds which comprise the basicmolecules in conventional acrylate photopolymers. One way to shift theabsorption bands to higher wavelength, is to replace most, if not all,of the hydrogen atoms in the conventional materials with heavierelements such as deuterium, fluorine, and chlorine. See, T. Kaino, inPolymers for Lightwave and Integrated Optics, Technology andApplications, L. A. Hornak, ed., p. 1, Dekker, 1992. The replacement ofhydrogen atoms with fluorine atoms is the easiest of these methods. Itis known in the art that optical loss at 1300 and 1550 nm can besignificantly reduced by increasing the fluorine to hydrogen ratio inthe polymer. It was recently reported that some perfluorinated polyimidepolymers have very low absorption over the wavelengths used in opticalcommunications. See, S. Ando, T. Matsuda, and S. Sasaki, Chemtech,1994-12, p.20. Unfortunately, these materials are not photocurable.

[0006] U.S. Pat. No. 5,274,174 discloses a new class of photocurablecompositions comprised of certain fluorinated monomers such asdiacrylates with perfluoro or perfluoropolyether chains which possesslow intrinsic absorption loss. It is, therefore, possible to make lowloss optical interconnects from a photocurable system include thesematerials.

[0007] Fluorine substitution in the polymer structure, however, alsoinduces some other less desirable changes in the polymer's physicalproperties. One such change is the decrease in refractive index. For ahighly fluorinated acrylate photopolymer, the refractive index decreasesto the 1.32 region when the H/F mole ratio reaches 0.25. For opticalinterconnect applications, to avoid loss of light, it is important thatthe refractive index of the core of a planar waveguide approximate andpreferably match that of the optical fiber (generally 1.45). Anotherproblem with fluorine substitution in the polymer is the decrease of thesurface energy of the resulting photopolymer film which results in itsreduced adhesion to other materials like substrates.

[0008] It is also important to be abovel to precisely control and finetune the refractive index of the photopolymer at the working wavelengthin optical waveguide and interconnect applications. A desired index ofrefraction can be produced by mixing photocurable monomers withdifferent refractive indices. Most photopolymers made from conventionalphotocurable monomers have refractive indices in the region of1.45-1.55. Depending on the application, it is often desirable to lowera photopolymer's refractive index. One way to do this is to mix lowrefractive index fluorinated monomers with conventionalhydrocarbon-based monomers. Unfortunately this is difficult toaccomplish because of the incompatibility or insolubility of thedifferent monomer systems. Thus, there is a need for photocurablecompositions which: (i) possess low optical loss in the near-infraredregion, (ii) possess a refractive index approaching traditional opticalfibers; and (iii) are compatible with both conventionalhydrocarbon-based and highly fluorinated monomers.

DESCRIPTION OF THE INVENTION

[0009] The photocurable monomer of the invention is a di-, tri- ortetra-acrylate which contains a chlorofluorinated or bromofluorinatedalkylene chain and has the formula:

[0010] wherein 0 in an integer of from 2-4; X is H, F, CH₃ or Cl and ispreferably H, or Cl.

[0011] R=—CH₂R_(F)CH₂—

[0012] and

[0013] R_(F)=—(CF₂CFX₁)_(a)CF₂—, —(CF₂CFX₁)_(a)—(CFX₂CF₂)_(b)—,

[0014] —(CF₂CFX₁)_(a)—(CF₂CFX₂)_(b)CF₂—, and

[0015] —(CF₂CFX₁)_(a)—(CH₂CY₁Y₂)_(b)—(CF₂CFX₁)_(d)CF₂—.

[0016] wherein X₁ is Cl or Br; X₂ is F, Cl or Br; Y, and Y₂ are the sameor different and are H, CH₃, F, Cl or Br; and a, b, and c are the sameor different and are integers of from 1-10 and preferably integers offrom 1-7.

[0017] In the preferred embodiments, the above mentioned monomerscontain chlorofluorinated or bromofluorinated alkylene chains whichcomprise chlorotrifluoroethylene or bromotrifluoroethylene repeatingunits and at least two terminal acrylate groups.

[0018] These monomers contain much less hydrogen than conventionalphotocurable monomers such that their inherent carbon-hydrogen bondabsorption is greatly reduced. In addition, the introduction of chlorineor bromine atoms into the molecule offsets the effect of fluorine on therefractive index of the monomer producing a material with an index ofrefraction between about 1.40-1 48 As a result, the monomers of theinvention are particularly useful in optical applications in the1300-1550 nm wavelength region. The monomers are also compatible withboth conventional hydrocarbon-based and highly fluorinated monomers.Because of this compatibility, it becomes possible to fine tune therefractive index and other physical properties of photocurablecompositions containing these photocurable monomer.

[0019] In a second embodiment, the invention relates to a photocurablecomposition comprising at least one photocurable monomer of theinvention and a photoinitiator.

[0020] In another embodiment, the invention relates to a process forproducing an optical device containing a light transmissive regioncomprising:

[0021] a) applying a film of a photocurable composition comprising aphotocurable monomer of the invention and a photoinitiator to asubstrate; b) imagewise exposing said composition to sufficient actinicradiation to form exposed and unexposed areas on the substrate; and c)removing the unexposed portions of the composition.

[0022] In still another embodiment, the invention relates to an opticaldevice comprising a light transmissive region wherein said lighttransmissive region comprises a photocurable composition of theinvention.

[0023] In yet another embodiment, the invention relates to a process forthe manufacture of an α,ω Diol of the formula:

HOCH₂—R_(F)—CH₂OH

[0024] comprising reacting a α,ω-Diester of the formula,

[0025] with aluminum hydride under conditions sufficient to produce saidα,ω Diol.

[0026] In still another embodiment the invention relates to a processfor the production of an α,ω-diol of the formula HOCH₂—R_(F)—CH₂OF whichcomprises reacting an α,ω-diester of the formula

[0027] with aluminum hydride under conditions sufficient to produce saidα,ω-diol;

[0028] wherein

[0029] R₁ is a straight or branched chain alkyl group of from 1 to about10 carbon atoms, and

[0030] R_(F)=—(CF₂CFX₁)_(a)CF₂—,—(CF₂CFX₁)_(a)—(CFX₂CF₂)_(b)—,

[0031] —(CF₂CFX₁)_(a)—(CF₂CFX2)_(b)CF₂—, or

[0032] —(CF₂CFX₁)_(a)—(CH₂CY₁Y₂)_(b)—(CF₂CFX₁)_(c)CF₂—

[0033] wherein X₁=Cl or Br; X₂=F, Cl, or Br; Y, and Y₂ are independentlyH, CH₃, F, Cl, or Br; a, b, and c are independently integers from 1 toabout 10.

[0034] All of the photocurable monomers of the invention may be made byusing or adapting methods known in the art. Methods for the preparationof certain α,ω-diols with chlorofluorinated backbones are known. See, B.Boutevin, A. Rousseau, and D Bosc, Jour. Polym. Sci., Part A, Polym.Chem., 30, 1279, 1993; B. Boutevin, A. Rousseau, and D Bosc, Fiber andIntegrated Optics, 13, 309, 1994; and B. Boutevin and Y. Pietrasanta,European Polym. Jour., 12, p.231, 1976.

[0035] The photocurable monomers of the invention may be prepared byfollowing the general reaction scheme outlined below wherein R_(F), andX have the meanings set forth above and R₁ is a straight or branchedchain alkyl group of from 1-10 and preferably 1-3 carbon atoms.

[0036] Preparation of the α,ω-Diester

[0037] Methods for the preparation of the α,ω-diester are known in theart. The diester may be prepared, for example by reducing with lithiumaluminum hydride the appropriate telomer of a halotrifluoroethylenemonomer. Examples of suitable halotrifluoroethylene monomers include:chlorotrifluoroethylene (or bromotrifluoroethylene), alone or mixturewith other vinyl monomers such as bromotrifluoroethylene (orchlorotrifluoroethylene), tetrafluoroethylene, trifluoroethylene,vinylidene fluoride, vinyl fluoride, vinyl chloride, vinylidenechloride, ethylene, and propylene. Preparation of α,ω-diesters with achlorofluorinated alkylene chain composed of chlorotrifluoroethylenemonomer units is described in U.S. Pat. Nos. 2,806,865 and 2,806,866

[0038] The prior art processes discussed above produce mixtures ofα,ω-diols because of the partial reduction of chlorine and bromine inthe α,ω-diester to hydrogen. Applicants have unexpectedly found that apure (not a mixture) α,ω-diol can be obtained by using an aluminumhydride reducing agent. Compare Example 1 and Examples 2-4 below.

[0039] Preparation of Triols and Tetraols

[0040] The α,ω-diols can be converted to triols and tetraols by methodsknown in the art. For example, a α,ω-triol can be obtained by: reactingthe α,ω-diol with a metal hydroxide base or a metal alkoxide base toproduce a metal salt of the α,ω-diol, reacting the metal salt with anallyl halide to produce an allyl ether of the α,ω-diol, and finallyreacting the allyl ether with a peroxyacid to produce a α,ω-triol. See,Turri, S.; Scicchitano, M.; and Tonelli, C., Jour. Polymer Science: PartA: Polymer Chemistry, 1966, 34, p.3263.

[0041] Preparation of the Di-, Tri- and Tetra-acrylates

[0042] The di-, tri-, and tetra- acrylates can also be prepared bymethods known in the art. For example, a triacrylate of the inventionmay be prepared by reacting the triol described above with an acryloylhalide in the presence of an organic base and an anhydrous aproticsolvent.

[0043] In addition to the photocurable monomer described above, otherphotocurable compounds which are known in the art may be incorporatedinto the photocurable compositions of the invention. These compoundsinclude monomers, oligomers and polymers containing at least oneterminal ethylenically unsaturated group and being capable of forming ahigh molecular weight polymer by free radical initiated, chainpropagating addition polymerization.

[0044] Suitable monomers include, but are not limited to, ethers, estersand partial esters of acrylic and methacrylic acid; aromatic andaliphatic polyols containing from about 2 to about 30 carbon atoms, andcycloaliphatic polyols containing from about 5 to about 6 ring carbonatoms. Specific examples of compounds within these classes are: ethyleneglycol diacrylate and dimethacrylate, diethylene glycol diacrylate anddimethacrylate, triethylene glycol diacrylate and dimethacrylate, hexanediacrylate and dimethacrylate, trimethylolpropane triacrylate andtrimethacrylate, dipentaerythritol pentaacrylate, pentaerythritoltriacrylate and trimethacrylate, alkoxylated bisphenol-A diacrylates anddimethacrylates (e g, ethoxylated bisphenol-A di-acrylate anddimethacrylate), propoxylated bisphenol-A diacrylates anddimethacrylates, ethoxylated hexafluorobisphenol-A diacrylates anddimethacrylates and mixtures of the above compounds. Preferred monomersinclude multifunctional aryl acrylates and methacrylates. More preferredaryl acrylate monomers include di-, tri- and tetra-acrylates andmethacrylates based on the bisphenol-A structure. Most preferred arylacrylate monomers are alkoxylated bisphenol-A diacrylates anddimethacrylates such as ethoxylated bisphenol-A di-acrylates anddimethacrylates, and ethoxylated hexafluorobisphenol-A diacrylates anddimethacrylates.

[0045] Suitable oligomers include, but are not limited to, epoxyacrylate oligomers, aliphatic and aromatic urethane acrylate oligomers,polyester acrylate oligomers, and acrylated acrylic oligomers. Epoxyacrylate oligomers (such as Ebercryl 600 by Radcure) are preferred.

[0046] Suitable polymers include, but are not limited to, acrylatedpolyvinyl alcohol, polyester acrylates and methacrylates, acrylated andmethacrylated styrene-maleic acid copolymers. Acrylated styrene-maleicacid copolymers such as Sarbox SR-454 sold by Sartomer are preferred.

[0047] The photocurable component is comprised of photocurable monomerA, and optionally the other photocurable compounds described above. Thephotocurable component is present in an amount sufficient to photocureand provide image differentiation upon exposure to sufficient actinicradiation. The amount of the photocurable component in the photocurablecomposition may vary widely. Typically the photocurable component ispresent in an amount of from about 35 to about 99% by weight of theoverall composition. In a preferred embodiment, the photocurablecomponent is present in an amount of from about 80 to about 99% byweight and more preferably from about 95 to about 99% by weight in theoverall composition. The weight ratio of monomer A to the otherphotocurable compounds may vary from about 1:9 to about 9:1. Preferablythe weight ratio ranges from about 1:1 to about 9:1.

[0048] The photocurable composition further comprises at least onephotoinitiator which photolytically generates activated species capableof inducing polymerization. Any photoinitiator known to be useful in thepolymerization of acrylates or methacrylates may be used in thephotocurable compositions of the invention. Suitable photoinitiatorsinclude aromatic ketone derivatives such as benzophenone, acrylatedbenzophenone, phenanthraquinone, 2,3-dichloronaphthoquinone, benzyldimethyl ketal and other aromatic ketones (e.g. benzoin), benzoin etherssuch as benzoin methyl ether, benzoin ethyl ether, benzoin isobutylether and benzoin phenyl ether. Preferred photoinitiators include1-hydroxy-cyclohexyl-phenyl ketone (Irgacure 184), benzoin, benzoinethyl ether, benzoin isopropyl ether, benzophenone, benzodimethyl ketal(Irgacure 651). α,α-diethyloxy acetophenone,α,ω-dimethyloxy-hydroxyacetophenone (Darocur 1173),1-[4-(2-hydroxyethoxy)phenyl]-2-hydroxy-2-methyl-propan-1-one (Darocur2959), 2-methyl-1-[4-methylthio)phenyl]-2-morpholino-propan-1-one(Irgacure 907),2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one (Irgacure369), poly{1-[4-(1-methylvinyl)phenyl]-2-hydroxy-2-methyl-propan-1-one }(Esacure KIP). [4-(4-methylphenylthio)-phenyl]- phenylmethanone(Quantacure BMS), and dicampherquinone. The most preferredphotoinutiators are those which tend not to yellow upon irradiation.Such photoinitiators include benzodimethyl ketal (Irgacure 651),α,α-dimethyloxy-a-hydroxy acetophenone (Darocur 1173),1-hydroxy-cyclohexyl-phenyl ketone (Irgacure 184), and1-[4-(2-hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-propan-1-one (Darocur2959).

[0049] The photoinitiator is present in an amount sufficient to effectphotopolymerization of the photocurable compound upon exposure tosufficient actinic radiation. The photoinitiator may comprise from about0.01 to about 10% by weight preferably from about 0.1 to about 6% byweight and most preferably from about 0.5 to about 4% by weight basedupon the total weight of the photocurable composition.

[0050] Various optional additives may also be added to the photocurablecompositions of the invention depending upon the application in whichsuch they are to be used. Examples of these optional additives includeantioxidants, photostabilizers, volume expanders, fillers (e.g., silicaand glass spheres), dyes, free radical scavengers, contrast enhancersand UV absorbers. Antioxidants include such compounds as phenols andparticularly hindered phenols including Irganox 1010 from Ciba-Geigy;sulfides; organoboron compounds; organophosphorous compounds; and N,N′-hexamethylenebis(3,5-di-ter(-butyl-4-hydroxyhydrocinnamamide)available from Ciba-Geigy under the tradename Irganox 1098.Photostabilizers and more particularly hindered amine light stabilizersinclude, but are not limited to, poly[(6-hexamethylene[2,2,6,6-tetramethyl-4-piperidyl)imino)] available from Cytec Industriesunder the tradename Cyasorb UV3346. Volume expanding compounds includesuch materials as the spiral monomers known as Bailey's monomer Suitabledyes include methylene green, methylene blue, and the like. Suitablefree radical scavengers include oxygen, hindered amine lightstabilizers, hindered phenols, and 2,2,6,6--tetramethyl-1-piperidinyloxyfree radical (TEMPO). Suitable contrast enhancers include other freeradical scavengers. UV absorbers include benzotriazoles andhydroxybenzophenone. These additives may be included in quantities,based upon the total weight of the composition of from about 0 to about6%, and preferably from about 0.1% to about 1%. Preferably allcomponents of the photocurable composition are in admixture with oneanother and more preferably in a substantially uniform admixture.

[0051] The photocurable compositions of this invention can be used inthe formation of the light transmissive element of an optical device.Illustrative of such devices are planar optical slab waveguides, channeloptical waveguides, ribbed waveguides, optical couplers, and splitters.The photocurable composition of this invention can also be used in theformation of negative working photoresists and other lithographicelements such as printing plates. In a preferred embodiment of theinvention, the photocurable composition is used for producing awaveguide comprising a substrate containing a light transmissiveelement. Such waveguides are formed by applying a film of thephotocurable composition of the invention to the surface of a suitablesubstrate. The film may, be formed by any method known in the art, suchas spin coating, dip coating, slot coating, roller coating, doctorblading, and evaporation.

[0052] The substrate may be any material on which it is desired toestablish a waveguide including semiconductor materials such as silicon,silicon oxide and gallium arsenide. In the event that the lighttransmissive region on the substrate is to be made from a photocurablematerial which has an index of refraction which is lower than that ofthe substrate, an intermediate buffer layer possessing an index ofrefraction which is lower than the substrate must be applied to thesubstrate before the photocurable composition is added. Otherwise, thelight loss in the waveguide will be unacceptable. Suitable buffers aremade from semiconductor oxides, lower refractive index polymers orspin-on silicon dioxide glass materials.

[0053] Once a film of the photocurable composition is applied to thesubstrate, actinic radiation is directed onto the film in order todelineate the light transmissive region. That is, the position anddimensions of the light transmissive device are determined by thepattern of the actinic radiation upon the surface of the film on thesubstrate. The photopolymers of the invention are conventionallyprepared by exposing the photocurable composition to sufficient actinicradiation. For purposes of this invention, “sufficient actinicradiation” means light energy of the required wavelength, intensity andduration to produce the desired degree of polymerize action in thephotocurable composition. Suitable sources of actinic radiation includelight in the visible, ultraviolet or infrared regions of the spectrum,as well as electron beam, ion or neutron beam or X-ray radiation Actinicradiation may be in the form of incoherent light or coherent light suchas light from a laser.

[0054] Sources of actinic light, exposure procedures, times, wavelengthsand intensities may vary widely depending on the desired degree ofpolymerization, the index of refraction of the photopolymer and otherfactors known to those of ordinary skill in the art. The selection andoptimization of these factors are well known to those skilled in theart.

[0055] It is preferred that the photochemical excitation be carried outwith relatively short wavelengths (or high energy) radiation so thatexposure to radiation normally encountered before processing (e.g., roomlights) will not prematurely polymerize the polymerizable material. Theenergy necessary to polymerize the photocurable compositions of theinvention generally ranges from about 5 mW/cm² to about 100 mW/cm² withtypical exposure times ranging from about 0.1 second to about 5 minutes.

[0056] After the photocurable composition has been polymerized to form apredetermined pattern on the surface of the substrate, the pattern isthen developed to remove the nonimage areas. Any conventionaldevelopment method can be used such as flushing the unirradiatedcomposition with a solvent. Suitable solvents include polar solvents,such as alcohols and ketones. The most preferred solvents are acetone,methanol, tetrahydrofuran and ethyl acetate.

[0057] The following non-limiting examples serve to illustrate theinvention.

EXAMPLE 1 Preparation and Reduction of CH₃OC(O)(CF₂CFCl)₂CF₂CO₂CHα,ω-diester by Aluminum Hydride

[0058] A. Preparation of CH₃OC(O)(CF₂CFCl)₂CF₂CO₂CH₃

[0059] To 225 parts of CCl₃(CF₂CFCl)₃Br was added 290 parts of fumingsulfuric acid containing 50% sulfur trioxide. The mixture was stirredand heated gradually from room temperature to 170° C. The mixture wasmaintained at that temperature for 6 hours and then cooled to 0° C.After this cooling, 240 parts of methanol was added dropwise to themixture. The solution was then heated to 150° C. for 2 hours, cooled toroom temperature and poured into 200 parts of ice-water. Then, thesolution was extracted with ether after which the ether layer wasevaporated (“ether workup”). The solution was next distilled to yield133 parts of the dimethylester, CH₃OC(O)(CF₂CFCl)₂CF₂COOCH₃ (81% yield)was obtained. The characterization results of this product areconsistent with the indicated structure.

[0060] B. Reduction of CH₃OC(O)(CF₂CFCl)₂CF₂CO₂CH₃ toHOCH₂(CF₂CFCl)₂CF₂CH₂OH with aluminum hydride

[0061] A solution of 310 part of 1.04M LiAlH₄ in tetrahydrofuran wasstirred at 0° C. under nitrogen To this solution was added slowly 17.8parts of 100% sulfuric acid. The solution was stirred for an additionalhour at room temperature. After settlement of the lithium sulfateprecipitate, 240 parts of the clear supernatant solution of AlH₃ (0.91M)was collected. To this 240 parts of AlH₃ solution which was stirred at0° C. was slowly added a solution of 33.7 parts of the above prepareddiester in 450 parts of tetrahydrofuran. The mole ratio of AlH₃ toCH₃OC(O)(CF₂CFCl)₂CF₂CO₂CH, was 2.6:1 After one hour, the excess hydridewas carefully hydrolyzed with 20 parts of a 1:1 mixture oftetrahydrofuran and water. After ether workup and distillation, 28 partsof the diol, HOCH₂(CF₂CFCl)₂CF₂CH₂OH was obtained (quantitative). Thecharacterization results of this product are consistent with theindicated structure.

EXAMPLE 2 Reduction of CH₃OC(O)(CF₂CFCl)₂CF₂CO₂CH₃ α,ω-diester byLithium Aluminum Hydride

[0062] A solution of 180 part of 1.04M LiAlH₄ in tetrahydrofuran wasstirred at 0° C. under nitrogen. To this solution was slowly added asolution of 30 parts of the diester CH₃OC(O)(CF₂CFCl)₂CF₂CO₂CH₃ in 450parts of tetrahydrofuran. The mole ratio of LiAlH₄ to the diester was2.6:1. After one hour, the excessive hydride was carefully hydrolyzedwith 20 parts of a 1:1 mixture of tetrahydrofuran and water. After etherworkup, 25 parts of crude product was obtained. GC-MS analysisidentified this crude product as a mixture of 3 main products: thetarget diol in which only the ester groups were reduced,HOCH₂(CF₂CFCl)₂CF₂CH₂OH; HOCH₂CF₂CFHCF₂CFClCF₂CH₂OH diol in which onechlorine atom was reduced and HOCH₂(CF₂CFH)₂CF₂CH₂OH in which bothchlorine atoms were reduced. The products were produced in a ratio of60:35:5 respectively.

EXAMPLE 3 Reduction of CH₃OC(O)(CF₂CFCl)₂CF₂CO₂CH₃ α,ω-diester withLithium Aluminum Hydride-Aluminum Chloride Complex

[0063] A solution of 165 parts of 1.04M LiAlH₄ in tetrahydrofuran wasstirred at 0° C. under nitrogen. To this solution was slowly added 22parts of anhydrous aluminum chloride. The mixture was stirred for onehour. A solution of 30 parts of the diester CH₃OC(O)(CF₂CFCl)₂CF₂CO₂CH₃in 450 parts of tetrahydrofuran was then slowly added. The mole ratio ofLiAlH₄: AlCl₃: CH₃OC(O)(CF₂CFCl)₂CF₂CO₂CH₃ was 2.2:2.2:1 respectively.GC-MS analysis identified the presence of the chlorine reduced diol inthe crude product.

EXAMPLE 4 Reduction of CH₃OC(O)(CF₂CFCl)₂CF₂CO₂CH₃ by Sodium Borohydride

[0064] To a stirred solution of 30 parts of the diesterCH₃OC(O)(CF₂CFCl)₂CF₂CO₂CH₃ in 450 parts of tetrahydrofuran at 0° C. andunder nitrogen, was slowly added 150 parts of 0.5M sodium borohydride in2-methoxyethyl ether. The mole ratio of NaBH₄ toCH₃OC(O)(CF₂CFCl)₂CF₂CO₂CH₃ was 2.0:1. GC-MS analysis identified thepresence of the chlorine reduced diol in the crude product.

[0065] The results from Examples 1-4 are described in Table 1 below.TABLE 1 Example: EX. 1 EX. 2 EX. 3 EX. 4 Reducing agent AlH₃ LiAlH₄LiAlH₄/AlCl₃ NaBH₄ (RA)* Ratio RA:diester: Theoretical 1.5:1 2:1 2:1 2:1Actual 2.6:1 2.5:1 2.2 1 2:1 Reduction of chlorine − + + +

[0066] The results show that even when present in excess, aluminumhydride does not result in reduction of chlorine atoms in the reduceddiol.

EXAMPLE 5 Preparation of CH₂═CHCO₂CH₂(CF₂CFCl)₂CF₂CH₂OC(O)CH═CH₂Diacrylate

[0067] 80 parts of the diol prepared in Example 1 were mixed with 56.3parts of triethylamine and 100 parts of methylene chloride and cooled to0° C. To this solution was slowly added with stirring and under nitrogen50 parts of freshly distilled acryloyl chloride in 100 parts ofmethylene chloride. After addition, the mixture was stirred for anadditional 24 hours and the temperature was returned to ambient. Themixture was treated with water and worked up with ethyl ether. The crudeproduct was purified by silica gel column chromatography (Merck #60)eluted with an ethyl acetate and hexane mixture. 28 parts of thepurified diacrylate, CH₂═CHCO₂CH₂(CF₂CFCl)₂CF₂CH₂OC(O)CH═CH₂ wasobtained. The characterization results are consistent with the indicatedstructure. ¹⁹F-NMR [δ (CF₃COOH), ppm]: 31.1 (2F), 35.5 (4F), and 53.6(2F); ¹H-NMR [δ, ppm] 4.66 (t, 4H), 6.13 (ABX, 6H); Mass spectra: 454(M⁺, 0.35%), 452 (M⁻, 0.57%), 426 ([M—CO or M—C₂H₄]⁺, 0.42%), 424 ([M—COor M—C₂H₄]⁺, 0.63%), 383 ([M—CH₂═CHCO₂]⁺, 0.21%), 381 ([M—CH₂═CHCO₂]⁺,0.31%), 85 ([CH₂═CHCO₂CH₂]⁺, 5.13%), 55 ([CH₂═CHCO]⁺, 100%), IR [film,cm⁻¹]: 2982 (w), 1747(vs), 1637(m), 1412(vs), 1299(s), 1262(s),1165(vs), 1110(s), 974(s). 806(m).

EXAMPLE 6 Preparation of CH₂═CClCO₂CH₂(CF₂CFCl)₂CF₂CH₂OC(O)CCl═CH₂ α,ClDiacrylate

[0068] The following materials were reacted according to the procedureset forth in Example 5 above: 44.5 parts of the diol prepared in Example1, 31.3 parts of triethylamine, 14 parts of a-chloroacryloyl chlorideand 100 parts of methylene chloride. 31 parts ofCH₂═CClCO₂CH₂(CF₂CFCl)₂CF₂CH₂OC(O)CCl═CH₂ were obtained. Thecharacterization results are consistent with the indicated structure.

EXAMPLE 7 Preparation of CH₂═CHCO₂CH₂(CF₂CFCl)₄CF₂CH₂OC(O)CH═CH₂Diacrylate

[0069] The following materials were reacted according to the procedureset forth in Example 5 above: 93 parts of HOCH₂(CF₂CFCl)₃CF₂CH₂OH, diol(prepared according to Example 1) 54 parts of triethylamine, 61 parts ofacryloyl chloride and 250 parts of methylene chloride. 22 parts of pureCH₂═CHCO₂CH₂(CF₂CFCl)₄CF₂CH₂OC(O)CH═CH₂ diacrylate were obtained, Thecharacterization results are consistent with the indicated structure.¹⁹F-NMR [δ (CF₃COOH), ppm]: 29.5˜32.0(m 6F), 36.0(s, 4F). 49.6˜55 0(m,4F); ¹H-NMR [δ, ppm] 4.6(t, J=13.6 Hz, 4H), 6.1(ABX system, 6H); MS: 684(M⁺, 0.25), 576 ([HOCH₂(CF₂CFCl)₄CF₂CH₂OH]⁻, 1.60), 460([HOCH₂(CF₂CFCl)₃CF₂CH₂OH]⁻, 1.67), 433 ([CH₂═CHCO₂CH₂(CF₂CFCl)₃]⁻), 344([HOCH₂(CF₂CFCl)₂CF₂CH₂OH]⁻, 0.71), 317 ([CH₂═CHCO₂CH₂(CF₂CFCl)₂]⁻,0.24), 135 ([CH₂═CHCO₂CH₂CF₂]⁻, 4.93), 85 ([CH₂═CHCO₂CH₂]⁺, 7.13), 55([CH2═CHCO]⁻, 100); IR [film, cm⁻¹]: 2983(w), 1748(vs). 1637(m).1411(s), 1261(s), 1165(vs), 1122(vs), 971(vs), 806(s)

EXAMPLE 8 Preparation of [CH₂═CHCO₂CH₂(CF₂CFCl)₂]₂ Diacrylate

[0070] A. Preparation of Cl₃CCF₂CFClCF₂CFClCFClCF₂CFClCF₂CCl₃ (precursorof α,ω-diester)

[0071] A mixture of 86 parts of acetic anhydride, 105 parts ofdichloromethane, 12.7 parts of granular zinc, and 81.8 parts ofCl₃C(CF₂CFCl)₂Br were stirred at 45° C. for 2 hours. The unreacted zincwas removed from the mixture and 40 parts of water were added. Theacetic anhydride was then hydrolyzed by the dropwise addition of 50parts of 3N H₂SO₄ and the mixture was washed with aqueous sodiumcarbonate, worked up with ether and then distilled. 13.4 parts of theunreacted Cl₃C(CF₂CFCl)₂Br, and 44.1 parts of the residue, showed two GCpeaks with a relative intensity of 1:6. The residue was then transferredinto a quartz tube with 125 parts of 1,1,2-trichlorotrifluoroethane.Chlorine gas was bubbled through the mixture for 4 hours while the tubewas irradiated with a 1,lamp at room temperature. After removal ofsolvent and fractional distillation, 44.5 parts of a single couplingproduct, Cl₃CCF₂CFClCF₂CFClCFClCF₂CFClCF₂CCl₃, was obtained. ¹⁹F-NMR(δ_(CF3COOH), ppm): 17.3-29.2 (8F), 41 0-48.6 (4F).

[0072] B. Preparation of H₃CO₂C(CF₂CFCl)₂—(CFClCF₂)₂CF₂CO₂CH₃α,ω-diester

[0073] 44.5 parts of Cl₃CCF₂CFClCF₂CFClCFClCF₂CFClCF₂CCl₃, was reactedaccording to the procedure set forth in Example 1A above to yield 30parts of H₃CO₂C(CF₂CFCl)₂—(CFClCF₂)₂CF₂CO₂CH₃ α,ω-diester.Characterization results are consistant with the indicated structure.

[0074] C. Preparation of HOCH₂(CF₂CFCl)₂—(CFClCF₂)₂CF₂CH₂OH α,ω-diol

[0075] 30 parts of H₃CO₂C(CF₂CFCl)₂—(CFClCF₂)₂CF₂CO₂CH₃ were reactedaccording to the procedure set forth in Example 1B above to yield 26parts of HOCH₂(CF₂CFCl)₂—(CFClCF₂)₂CF₂CH₂OH α,ω-diol. Thecharacterization results are consistant with the indicated structure.

[0076] D. Preparation of [CH₂═CHCO₂CH₂(CF₂CFCl)₂—]₂ diacrylate

[0077] 13 parts of HOCH₂(CF₂CFCl)₂—(CFClCF₂)₂CF₂CH₂OH was reactedaccording to the procedure set forth in Example 5 above to yield 15parts of [CH₂═CHCO₂CH₂(CF₂CFCl)₂—]₂ were obtained. The characterizationresults are consistant with the indicated structure.

EXAMPLE 9 Preparation ofHOCH₂CH(OH)CH₂OCH₂(CF₂CFCl)₃CF₂CH₂OCH2OH(OH)CH₂OH α,ω-tetraol

[0078] HOCH₂(CF₂CFCl)₃CF₂CH₂OH diol was prepared according to theprocedure outline in Example 1 above. Then, to a stirred solution of46.1 parts of the HOCH₂(CF₂CFCl)₃CF₂CH₂OH diol in 200 parts of anhydroust-butanol was slowly added at 0° C. a solution of 21.6 parts ofpotassium t-butoxide in 100 parts of t-butanol. After 2 hours, thetemperature of the mixture was raised to 30° C. and 25 parts of allylbromide was added The mixture was stirred overnight. After filtrationand vacuum removal of excess allyl bromide and most of the t-butanol,the residue was poured into 300 parts of water. After ether workup, 54parts of diallyl product was obtained. ¹⁹F and ¹H-NMR proved thecompleteness of the allylation.

[0079] 54 parts of the diallyl product was then dissolved in 200 partsof methylene chloride and a mixture of 20 parts of triethylammoniumtrifluoroacetate with 10 parts of trifluoroacetic acid was added. Tothis chilled mixture was then added a trifluoroperoxyacetic acidsolution (which was made by slowly adding 11 parts of 35% hydrogenperoxide to 25 parts of trifluoroacetic anhydride at 0° C.). Theresulting mixture wax stirred for 2 hours. After 6 hours, the mixturewas poured into ice-water. The organic layer was further washed withwater and vacuum dried to yield 50 parts ofHOCH₂CH(OH)CH₂OCH₂(CF₂CFCl)₃CF₂CH₂OCH₂CH(OH)CH₂OH tetraol. Thecharacterization results are consistant with the indicated structure.

EXAMPLE 10 Preparation ofCH₂═CHCO₂CH₂CH[OC(O)CH═CH₂]CH₂OCH₂(CF₂CFCl)₃CF₂CH₂OCH₂CH(OC(O)CH═CH₂)CH₂OOC(O)CH═CH₂Tetracrylate

[0080] 25 parts of HOCH₂CH(OH)CH₂OCH₂(CF₂CFCl)₃CF₂CH₂OCH2CH(OH)CH₂OHwere reacted according to the procedure set forth in Example 5 above toyield 15 parts ofCH₂═CHCO₂CH₂CH[OC(O)CH═CH₂]CH₂OCH₂(CF₂CFCl)₃CF₂CH₂OCH₂CH(OC(O)CH═CH₂)CH₂OOC(O)CH═CH₂ tetracrylate. The characterization resultsare consistant with the indicated structure.

EXAMPLE 11 Preparation ofCH₂═CClCO₂CH[OC(O)CCl═CH₂]CH₂OCH₂(CF₂CFCl)₃CF₂CH₂OCH₂CH[OC(O)CCl═CH₂]CH₂OOC(O)CCl═CH₂tetra-α-Cl Acrylate

[0081] 25 parts of HOCH₂CH(OH)CH₂OCH₂(CF₂CFCl)₃CF₂CH₂OCH2CH(OH)CH₂OHwere reacted according to the procedure set forth in Example 6 above toyield 12 parts ofCH₂═CClCO₂CH[OC(O)CCl═CH₂]CH₂OCH₂(CF₂CFCl)₃CF₂CH₂OCH₂CH[OC(O)CCl═CH₂]CH₂OOC(O)CCl═CH₂tetra α-Cl-acrylate. The characterization results are consistant withthe indicated structure.

EXAMPLE 12 Preparation ofCH₂═CHCO₂CH₂(CF₂CFCl)₃CF₂CH₂OCH2CH[OC(O)CH═CH₂]CH₂OOC(O)CH═CH₂Triacrylate

[0082] 25 parts of HOCH₂(CF₂CFCl)₃CF₂CH₂OCH2CH(OH)CH₂OH triol (preparedaccording to the procedure outlined in Example 9 above except that theamount of the diol starting material was doubled (92 parts)) werereacted according to the procedure set forth in Example 5 above to yield10 parts ofCH₂═CHCO₂CH₂(CF₂CFCl)₃CF₂CH₂OCH2CH[OC(O)CH═CH₂]CH₂OOC(O)CH═CH₂triacrylate. The characterization results are consistant with theindicated structure.

EXAMPLE 13

[0083] Comparison of the refractive indices and near-IR absorption ofconventional hydrocarbon-based diacrylates, highly fluorinateddiacrylates and the chlorofluorodiacrylates of the invention

[0084] The refractive indices and near-IR absorption of three diacrylatemonomers are compared in Table 2 below: TABLE 2 Index of Near IRRefraction* Absorption** H₂C═CHCO₂CH₂(CF₂CFCl)₂CF₂CH₂OC(O)CH═CH₂ 1.4221lowest H₂C═CHCO₂CH₂(CF₂)₄CH₂OC(O)CH═CH₂ 1.3891 mediumH₂C═CHCO₂CH₂(CH₂)₄CH₂OC(O)CH═CH₂ 1.4560 highest

[0085] This example demonstrates that the chlorofluoroacrylates of theinvention have indices of refraction which approximate the indices ofrefraction of optical fibers making them more suitable for opticalinterconnect applications than the highly fluorinated diacrylates. Thedata also show that the diacrylates of the invention have lower IRabsorption which makes them suitable for low loss optical applications.

EXAMPLES 14-22 General Procedure used to Prepare the PhotopolymersDescribed Below

[0086] The photocurable monomer(s) and photoinitiator used in theexamples which follow were stirred at 30-50° C. in a brown lasscontainer under nitrogen for 5-8 hours. The mixture was thenpressure-filtered through a 0.2 micron PTFE membrane to obtain ahomogeneous clear photocurable composition. The composition wasspin-coated onto a silicon wafer or a quartz plate to form a 2-10 micronthick liquid layer. The plate was then irradiated under medium pressuremercury UV lamp in a nitrogen atmosphere for 0 1-60 seconds to obtain atough solid coating.

EXAMPLE 14 Preparation of H₂C═CHCO₂CH₂(CF₂CFCl)₂CF₂CH₂OC(O)CH═CH₂Photopolymer

[0087] The monomer prepared in Example 5 above was mixed with 2.0 wt. %of α,α-dimethyloxy-α-hydroxyacetophenone (Darocur 1173) into ahomogenous composition and photocured according to the procedure setforth above. The resulting product was a clear, tough, solid polymerfilm. The refractive indices of the monomer and the polymer are 1.4221(at 589 nm) and 1.4586 (at 633 nm) respectively.

EXAMPLE 1 Preparation of H₂C═CClCO₂CH₂(CF₂CFCl)₂CF₂CH₂OC(O)CCl═CH₂Photopolymer

[0088] The monomer prepared in Example 6 above was mixed with 2.0 wt. %of benzodimethyl ketal (Irgacure 651) into a homogeneous composition andphotocured according to the procedure set forth above. The resultingproduct was a clear, tough, solid polymer film.

EXAMPLE 16 Preparation ofH₂C═CHCO₂CH₂(CF₂CFCl)₄CF₂CH₂C(O)CH═CH₂Photopolymer

[0089] The monomer prepared in Example 7 above was mixed with 1 wt. % LR8893X (Ciba-Geigy) into a homogeneous composition and photocuredaccording to the procedure set forth above. The resulting product was aclear, tough, solid polymer film. The refractive indices of the monomerand the polymer are 1.4232 (at 589 nm) and 1.4416 (at 810 nm)respectively.

EXAMPLE 17 Preparation of [CH₂═CHCO₂CH₂(CF₂CFCl)₂—]₂Photopolymer

[0090] The monomer prepared in Example 8 above was mixed with 1.5 wt %of benzodimethyl ketal (Irgacure 651) into a homogeneous composition andphotocured according to the procedure set forth above The resultingproduct was a clear, tough, solid polymer film. The refractive indicesof the monomer and the polymer are 1.4482 (at 589 nm) and 1.4724 (at 633nm) respectively.

EXAMPLE 18 Preparation ofCH₂═CHCO₂CH₂CH[OC(O)CH═CH₂]CH₂OCH₂(CF₂CFCl)₃CF₂CH₂OCH₂CH[OC(O)CH═CH₂]CH₂OOC(O)CH═CHTetracrylate

[0091] The monomer produced in Example 10 was mixed with 1.5 wt % ofbenzodimethyl ketal (Irgacure 651) to produce a homogeneous composition.The composition was photocured according to the procedure set forthabove. The resulting product was a clear, tough, solid polymer film.

EXAMPLE 19 Preparation of a Mixture ofH₂C═CHCO₂CH₂(CF₂CFCl)₄CF₂CH₂OC(O)CH═CH₂ (A) andH₂C═CClCO₂CH₂(CF₂CFCl)₄CF₂CH₂OC(O)CCl═CH₂ (B)

[0092] Monomers A and B were mixed together in three weight ratios:10.3/89.7; 32.6/67.4; and 49.4/50.6 and each of the resulting mixtureswas combined with 1 wt. % of LR 8893X as photoinitiator. Eachcomposition was photocured according to the procedure set forth above.The refractive indices of resulting photocurable compositions and thephotocured polymers made from these compositions are listed in Table 3below: TABLE 3 Ratio of Refractive Refractive monomers in RefractiveIndex of index of photocurable index of photocured photocuredcomposition photocurable polymer polymer (A/B) composition at 810 nm at1150 nm 10.3/89.7 1.4377 1.4552 1.4505 32.6/67.4 1.4349 1.4498 1.447049.4/50.6 — 1.4488 1.4425

[0093] This example shows that the diacrylates of the invention may becombined to produce a polymer of desired refractive index.

EXAMPLE 20 Preparation of a Mixture ofH₂C═CHCO₂CH₂(CF₂CFCl)₃CF₂CH₂OC(O)CH═CH₂ and a hydrocarbon Diacrylate[(CH₃)CC₆H₄O(CH₂)₂O₂CCH═CH₂]₂ (EBDA) SR-349)

[0094] H₂C═CHCO₂CH₂(CF₂CFCl)₃CF₂CH₂OC(O)CH═CH₂ monomer was mixed with[(CH₃)CC₆H₄O(CH₂)₂O₂CCH═CH₂]₂ (ethoxylated bisphenol-A diacrylate, EBDA,Sartomer SR349) in a weight ratio of 11.2/88.8, respectively, to give ahomogeneous mixture. LR 8893X (0.7 wt % ) was added to this mixture asthe photoinitiator. The composition was photocured according to theprocedure set forth in Example 21 above. The resulting product was aclear, tough, solid polymer film. The refractive indices of thephotocurable composition and the photopolymer are 1.4429 (at 589 nm) and1.4512 (at 1550 nm), respectively.

[0095] This example shows that the diacrylates of the invention may becombined with (are compatible with ) other conventionalhydrocarbon-based monomers.

EXAMPLE 21 Preparation of a Mixture ofH₂C═CHCO₂CH₂(CF₂CFCl)₃CF₂CH₂OC(O)CH═CH₂ and a Fluorinated Diacrylate[CH═CHCO₂CH₂CF(CF₃)O(CF(CF₃)CF₂O)₂CF₂CF₂]₂

[0096] H₂C═CHCO₂CH₂(CF₂CFCl)₃CF₂CH₂OC(O)CH═CH₂ monomer was mixed with ahighly fluorinated diacrylate,[CH₂CHCO₂CH₂CF(CF₃)O(CF(CF₃)CF₂O)₂CF₂CF₂]₂, in a weight ratio of 70/30,respectively, to give a homogeneous mixture. LR 8893X 0.7 wt. %, wasadded to this composition as photoinitiator. The composition wasphotocured according to the procedure set forth above. The resultingproduct was a clear, tough, solid polymer film The refractive indices ofthe photocurable composition and the photocured polymer are 1.4092 (at589 nm) and 1.4289 (at 633 nm), respectively The refractive indices ofthe two homopolymers, H₂C═CHCO₂CH₂(CF₂CFCl)₃CF₂CH₂OC(O)CH═CH₂ and[CH₂═CHCO₂CH₂CF(CF₃)O(CF(CF₃)CF₂O)₂CF₂CF₂]₂, are 1.4435 (at 633 nm) and1.3484 (at 633 nm), respectively.

[0097] This example shows that the diacrylates of the invention may becombined with (are compatible with) highly fluorinated monomers

EXAMPLE 22 Preparation of a Polymer Waveguide using a ChlorofluorinatedDiacrylate of the Invention

[0098] The photocurable compositions of each of Examples 14-21 is coatedonto a glass substrate to a thickness of 6 to 10 μm. The coating isirradiated in a nitrogen atmosphere for 30 seconds through a quartz maskwith light from a mercury-xenon arc lamp at 11.3 mW/cm². The mask isdesigned to produce a single-mode star coupler consisting of taperedwaveguides of from 5.5 to 8.5 μm width having decreasing spacing betweenthe guides down to 3.5 μm. Following exposure, the coating is developedby flushing with acetone from end to end to produce free-standing ribwaveguides of about 5 to 9 μm width.

In the claims:
 1. A photocurable compound of the formula

wherein o=2, 3, or 4, X=H, F, CH₃, or Cl; and R=—CH₂R_(F)CH₂—,

wherein R_(F)=—(CF₂CFX₁)_(a)CF₂—,

—(CF₂CFX₁)_(a)—(CF₂CFX₂)_(b)CF₂—, or—(CF₂CFX₁)_(a)—(CH₂CY₁Y₂)_(b)—(CF₂CFX₁)_(c)CF₂— wherein X₁=Cl or Br,X₂=F, Cl, or Br; Y₁ and Y₂ are independently H, CH₃, F, CL or Br; a, b,and c are independently integers from 1 to about
 10. 2. The photocurablecompound of claim 1 wherein a, b, and c are independently integers from1 to about
 7. 3. The photocurable compound of claim 1 comprisingchlorotrifluoroethylene or bromotrifluoroethylene repeating units andhaving at least two terminal acrylate groups.
 4. The photocurablecompound of claim 1 which comprisesCH₂═CHCO₂CH₂(CF₂CFCl)₂CF₂CH₂OC(O)CH═CH₂;CH₂═CClCO₂CH₂(CF₂CFCl)₂CF₂CH₂OC(O)CCl═CH₂,CH₂═CHCO₂CH₂(CF₂CFCl)₄CF₂CH₂OC(O)CH═CH₂,CH₂═CHCO₂CH₂CH[OC(O)CH═CH₂]CH₂OCH₂(CF₂CFCl)₃CF₂CH₂OCH₂CH[OC(O)CH═CH₂]CH₂OOC(O)CH═CH₂;CH₂═CClCO₂CH₂CH[OC(O)CCl═CH₂]CH₂OCH₂(CF₂CFCl)₃CF₂CH₂OCH₂CH[OC(O)CCl═CH₂]CH₂OOC(O)CCl═CH₂;CH₂═CHCO₂CH₂(CF₂CFCl)₃CF₂CH₂OCH₂CH(OC(O)CH═CH₂]CH₂OOC(O)CH═CH₂;[CH₂═CHCO₂CH₂(CF₂CFCl₂—]₂;CH₂═CHCO₂CH₂CH[OC(O)CH═CH₂]CH₂OCH₂(CF₂CFCl)₃CF₂CH₂OCH₂CH[OC(O)CH═CH₂]CH₂OOC(O)ch═CH₂, CH₂═CClCO₂CH₂(CF₂CFCl)₄CF₂CH₂OC(O)CCl═CH₂;H₂C═CHCO₂CH₂(CF₂CFCl)₃CF₂CH₂OC(O)CH═CH₂;H₂C═CHCO₂CH₂(CF₂CFCl)₃CF₂CH₂OC(O)CH═CH₂ and mixtures thereof.
 5. Aphotocurable composition comprising at least one photocurable compoundaccording to claim 1 sand at least one photoinitiator.
 6. Thephotocurable composition of claim 5 wherein the photocurable compound ispresent in an amount of from about 35% to about 99.9% by weight of thephotocurable composition.
 7. The photocurable composition of claim 6further comprising at least one ethylenically unsaturated monomer,oligomer, or polymer compound.
 8. The photocurable composition of claim7 wherein the photocurable compound and the at least one ethylenicallyunsaturated monomer, oligomer, or polymer compound are present in atotal amount from about 35% to about 99.9% by weight of the photocurablecomposition and at a weight ratio of the photocurable compound to the atleast one ethylenically unsaturated monomer, oligomer, or polymercompound of from about 1:9 to about 9:1.
 9. The photocurable compositionof claim 5 wherein the photoinitiator is present in an amount of fromabout 0.01% to about 10% by weight of the overall composition.
 10. Thephotocurable composition of claim 5 further comprising one or moreadditives selected from the group consisting of antioxidants,photostabilizers, volume expanders, fillers, dyes, free radicalscavengers, contrast enhancers and UV absorbers.
 11. The photocurablecomposition of claim 10 wherein the one or more additives are present inan amount from about 0.1% to about 6% by weight of the overallcomposition.
 12. A process for producing an optical device whichcomprises applying a layer of the photocurable composition of claim 5onto a substrate, imagewise exposing the photocurable composition toactinic radiation to form exposed and nonexposed areas on the substrate,and removing the imagewise nonexposed areas while leaving the imagewiseexposed areas on the substrate.
 13. The process of claim 12 wherein theimagewise nonexposed areas are removed with a solvent developer.
 14. Theoptical device produced according to the process of claim 12 .
 15. Theoptical device of claim 14 which is a waveguide, a splitter, a router, acoupler or a combiner.
 16. An optical device which comprises a layer ofa patterned and photocured composition according to claim 5 .
 17. Anoptical device which comprises a substrate, and a layer of a patternedand photocured composition according to claim 5 on the substrate. 18.The optical device of claim 11 wherein the substrate comprises silicon,silicon oxide, or gallium arsenide.
 19. A process for the production ofan α,ω-diol of the formula HOCH₂—R_(F)—CH₂OF which comprises reacting anα,ω-diester of the formula

with aluminum hydride under conditions sufficient to produce saidα,ω-diol; wherein R₁ is a straight or branched chain alkyl group of from1 to about 10 carbon atoms; andR_(F)=—(CF₂CFX₁)_(a)CF₂—,—(CF₂CFX₁)_(a)—(CFX₂CF₂)_(b)—,—(CF₂CFX₁)_(a)—(CF₂CFX₂)_(b)CF₂—, or—(CF₂CFX₁)_(a)—(CH₂CY₁Y₂)_(b)—(CF₂CFX₁)_(c)CF₂— wherein X₁═Cl or Br;X₂=F, Cl, or Br; Y₁ and Y₂ are independently H, CH₃, F, Cl, or Br; a, b,and c are independently integers from 1 to about
 10. 20. A process forproducing at least one di-, tri-, or tetraacrylate which comprises: A)reducing an α,ω-diester of the formula:

with AlH₃ under conditions sufficient to produce an α,ω-diol of theformula: HOCH₂—R_(F)—CH₂OH; and then B) performing either step a, b, orc: a) reacting the α,ω-diol produced by step A with at least oneacryloyl halide in the presence of at least one organic base and atleast one anhydrous aprotic solvent, under conditions sufficient toproduce a diacrylate of the formula:

b) i) reacting the α,ω-diol produced by step A with at least one metalhydroxide base or metal alkoxide base under conditions sufficient toproduce a metal salt of the α,ω-diol, and then ii) reacting the metalsalt produced by step b)i) with about one molar equivalent of an allylhalide per molar equivalent of molar salt under conditions sufficient toproduce an allyl ether of the α,ω-diol; and then iii) reacting the allylether produced by step b)ii) with at least one peroxyacid underconditions sufficient to produce a triol of the formula:

and then iv) reacting the triol produced by step b)iii) with at leastone acryloyl halide in the presence of at least one organic base and atleast one anhydrous aprotic solvent, under conditions sufficient toproduce a triacrylate of the formula:

c)i) reacting the α,ω-diol produced by step A with at least one metalhydroxide base or metal alkoxide base under conditions sufficient toproduce a metal salt of the α,ω-diol, and then ii) reacting the metalsalt produced by step c)i) with about two molar equivalents of an allylhalide per molar equivalent of metal salt under conditions sufficient toproduce an allyl ether of the α,ω-diol; and then iii) reacting the allylether produced by step c)ii) with at least one peroxyacid underconditions sufficient to produce a tetraol of the formula:

iv) reacting the tetraol produced by step c)ii) with at least oneacryloyl halide in the presence of at least one organic base and atleast one anhydrous aprotic solvent under conditions sufficient toproduce a tetraacrylate of the formula:

wherein R₁ is a straight or branched chain alkyl group of from 1 toabout 10 carbon atoms; R_(F)=—(CF₂CFX₁)_(a)CF₂—,—(CF₂CFX₁)_(a)—(CFX₂CF₂)_(b)—, —(CF₂CFX₁)_(a)—(CF₂CFX₂)_(b)CF₂—, or—(CF₂CFX₁)_(a)—(CH₂CY₁Y₂)_(b)—(CF₂CFX₁)_(c)CF₂— wherein X₁=Cl or Br;X₂=F, Cl, or Br; Y₁ and Y₂ are independently H, CH₃, F, Cl, or Br, a, b,and c are independently integers from 1 to about
 10. 21. The process ofclaim 20 which comprises performing step a to produce the diacrylate.22. The process of claim 20 which comprises performing step b to producethe triacrylate.
 23. The process of claim 20 which comprises performingstep c to produce the tetraacrylate.
 24. A process for producing atleast one diacrylate which comprises: A) reducing an α,ω-diester of theformula:

with AlH₃ under conditions sufficient to produce an α,ω-diol of theformula: HOCH₂—R_(F)—CH₂OH; and then B) reacting the α,ω-diol producedby step A with at least one acryloyl halide in the presence of at leastone organic base and at least one anhydrous aprotic solvent, underconditions sufficient to produce a diacrylate of the formula:

wherein R₁ is a straight or branched chain alkyl group of from 1 toabout 10 carbon atoms;R_(F)=—(CF₂CFX₁)_(a)CF₂—,—(CF₂CFX₁)_(a)—(CFX₂)_(b)—,—(CF₂CFX₁)_(a)—(CF₂CFX₂)_(b)CF₂—, or—(CF₂CFX₁)_(a)—(CH₂CY₁Y₂)_(b)—(CF₂CFX₁)_(c)CF₂— wherein X₁=Cl or Br;X₂=F, Cl, or Br; Y₁ and Y₂ are independently H, CH, F, Cl, or Br; a, b,and c are independently integers from 1 to about
 10. 25. A process forproducing at least one triacrylate which comprises: A) reducing anα,ω-diester of the formula:

with AlH₃ under conditions sufficient to produce an α,ω-diol of theformula: HOCH₂—R_(F)—CH₂OH; and then B) i) reacting the α,ω-diolproduced by step A with at least one metal hydroxide base or metalalkoxide base under conditions sufficient to produce a metal salt of theα,ω-diol; and then ii) reacting the metal salt produced by step i) withabout one molar equivalent of an allyl halide per molar equivalent ofmolar salt under conditions sufficient to produce an allyl ether of theα,ω-diol; and then iii) reacting the allyl ether produced by step ii)with at least one peroxyacid under conditions sufficient to produce atriol of the formula:

and then iv) reacting the triol produced by step iii) with at least oneacryloyl halide in the presence of at least one organic base and atleast one anhydrous aprotic solvent, under conditions sufficient toproduce a triacrylate of the formula:

wherein R₁ is a straight or branched chain alkyl group of from 1 toabout 10 carbon atoms;R_(F)—(CF₂CFX₁)_(a)CF₂—,—(CF₂CFX₁)_(a)—(CFX₂CF₂)_(b)—,—(CF₂CFX₁)_(a)—(CF₂CFX₂)_(b)CF₂—, or—(CF₂CFX₁)_(a)—(CH₂CY₁Y₂)_(b)—(CF₂CFX₁)_(c)CF₂— wherein X₁=Cl or Br;X₂=F, Cl, or Br; Y₁ and Y₂ are independently H, CH₃, F, Cl, or Br; a, b,and c are independently integers from 1 to about
 10. 26. A process forproducing at least one tetraacrylate which comprises: A) reducing anα,ω-diester of the formula:

with AlH₃ under conditions sufficient to produce an α,ω-diol of theformula: HOCH₂—R_(F)—CH₂OH; and then B) i) reacting the α,ω-diolproduced by step A with at least one metal hydroxide base or metalalkoxide base under conditions sufficient to produce a metal salt of theα,ω-diol; and then ii) reacting the metal salt produced by step i) withabout two molar equivalents of an allyl halide per molar equivalent ofmetal salt under conditions sufficient to produce an allyl ether of theα,ω-diol; and then iii) reacting the allyl ether produced by step ii)with at least one peroxyacid under conditions sufficient to produce atetraol of the formula:

and then iv) reacting the tetraol produced by step iii) with at leastone acryloyl halide in the presence of at least one organic base and atleast one anhydrous aprotic solvent under conditions sufficient toproduce a tetraacrylate of the formula:

wherein R₁ is a straight or branched chain alkyl group of from 1 toabout 10 carbon atoms;R_(F)=(CF₂CFX₁)_(a)CF₂—,—(CF₂CFX₁)_(a)—(CFX₂CF₂)_(b)—,—(CF₂CFX₁)_(a)—(CF2CFX₂)_(b)CF₂—, or—(CF₂CFX₁)_(a)—(CH₂CY₁Y₂)_(b)—(CF₂CFX₁)_(c)CF₂— wherein X₁=Cl or Br;X₂=F, Cl, or Br; Y₁ and Y₂ are independently H, CH₃, F, Cl, or Br; a, b,and c are independently integers from 1 to about 10.